Of course Troy Davis's mother is happy that the Georgia board of pardons and paroles voted to stay her son's execution just a day before he was scheduled to die for a murder he didn't commit. And I confess to being very pleasantly surprised; it seemed to me overwhelmingly likely that Davis was a goner, and the movement to remove procedural barriers to execution in the United States was about to claim its first demonstrably innocent victim.

First, the established facts. One Friday night in 1989, two men scuffled in a Burger King parking lot in Savannah, Georgia. An off-duty police officer tried to intervene, and one of the men shot the cop to death. The (probable) gunman then coolly went to the police and identified Davis, an African American recent high-school graduate, as the killer. The police then dutifully went about turning that false accusation into a capital sentence.

The gun was never found, so building case meant getting people to identify Davis as the killer. Nine people ultimately testified either that they saw Davis shoot the cop or that they heard him confess to the shooting.

But much of this testimony was dodgy. Here's a piece of a statement from one of the key witnesses, who was 16 at the time of the shooting. ("Red" is the man who first accused Davis):

"I told them it was Red and not Troy who was messing with that man, but they didn't want to hear that. The detectives told me, 'Fine, have it your way. Kiss your life goodbye because you're going to jail.' After a couple of hours of the detectives yelling at me and threatening me, I finally broke down and told them what they wanted to hear."

Of the nine, seven have now formally recanted. Others have identified "Red" as the killer. But having succeeded in obtaining a death sentence against an innocent man, prosecutors have stuck with it. Troy Davis was scheduled to be executed Tuesday. But on Monday, just hours before he was set to die, the Georgia pardons board granted him a 90-day stay of execution.

That's fine for starters. But here's the problem: apparently, the board can't undo Davis's conviction. It can only commute his sentence to life without parole. That outcome makes no sense whatsoever.

If Davis is innocent, then he no more belongs in an ordinary cellblock than he does on Death Row. If he's guilty, then a commutation seems unjustified. Whoever it was that harassed a homeless man to try to make him give up a can of beer and then shot the off-duty policy officer who tried to come to the rescue, it's hard to see why that person is any less deserving of death than any other capital convict.

Troy Davis may well be the fit object of mercy. But what he's asking for is justice: a fair hearing for his claim that he never committed the crime of which he was convicted. The pardons board has no particular qualifications to conduct that inquiry, which is properly a matter for the courts.

But the federal courts can't hear Davis's claim. The Anti-terrorism and Effective Death Penalty Act - passed in the wake of the Oklahoma City bombing by a Republican congress and signed by a Democratic president - makes it virtually impossible to introduce new evidence after the initial appeal is denied; the slogan is "finality of verdict."

Following that law, the appeals courts in the Davis case have refused to even examine the recantations because they weren't introduced in a timely fashion. So in the Alice-in-Wonderland world of jurisprudence, Davis is "legally guilty" of a murder he in all likelihood never committed, with no procedural avenue by which to turn his innocence-in-fact in to legally cognizable "actual innocence."

Davis's court-appointed trial lawyer, who also handled the first appeal that is mandatory in death penalty cases, did a remarkably - but, alas, not unusually - shoddy job, and Davis, now 38, may yet die for that lawyer's professional sins. That's an outage.

The courthouse door should never be shut to the innocent victim of a miscarriage of justice, no matter how old his conviction or how many mistakes his lawyers made along the way.

Davis's new lawyers hope to use the 90 days to persuade the Georgia courts to hear exonerating testimony. So justice may yet be served, especially with the national attention the case is now getting.

But the real lesson here is simple: Troy Davis should have chosen more prosperous parents, who could have afforded a competent lawyer. Better yet, he should have gone to Duke and taken up lacrosse.